The stock has not traded since that confrontation. The final trade on the New York Stock Exchange was for $18.93, a price that valued the company at $1.1 billion. At its peak in November, it had a market capitalization of $2.4 billion.

It now seems likely that the stock is worthless. It is a real company, but its revenue and profits probably were a small fraction of the amounts reported. The existence of the “significant” debt means that whatever assets are left are likely to be owned by the banks, not the investors.

Deloitte may have decided to check the numbers again because it knew a growing group of bears on the stock had been challenging the Longtop story as too good to be true, questioning both its financial statements and the claims it made for its software. A month earlier, Deloitte resigned as the auditor of another Chinese company, China MediaExpress, in part because of questions about bank confirmations.

It is never good for an auditor to have certified a fraud, but Deloitte seems to have acted properly. It got bank confirmations, and it got them directly from the banks rather than relying on the company to provide them, as PricewaterhouseCoopers had done when it failed to notice a huge fraud at Satyam, an Indian technology company.